1. Field of the Invention
The present invention relates to an apparatus for controlling a warp tension to an appropriate tension value when a loom stops.
2. Description of the Related Art
Japanese Patent Publication No. 36-4029 discloses a technique in which the warp tension is set to be slackened by an electronic control system when a loom stops.
It is effective that the warp tension is slackened when the loom stops for a long period of time. On the contrary, a weaving bar is liable to be generated when the loom stops for a short period of time; hence; the slackening of the warp tension is not an effective means. That is, it is necessary to return the tension value to a normal value when a cloth fell is returned to a regular position in the case of the restarting of the loom after the slackening of the warp. However, inasmuch as a delicate setting of the tension value depends on the kind of texture in consideration of the stretch of the warp during the stoppage of the loom, it is not easy to adjust the warp tension or the position of the cloth fell. If such an adjustment is erroneously made, it causes a new weaving bar.
Thus, even if the warp tension is not slackened when the loom stops for a short period of time, a weaving bar is rarely generated. Accordingly, at this time, it is preferable for the warp tension to not be slackened but kept as it is without generating the cause of the weaving bar due to the slackening of the warp tension.
Particularly, in the recent working or operating mode, the stop time of the loom is largely differentiated depending on the mode of working. That is, when the loom stops during normal working hours, an operator removes the cause of the stoppage in a relatively short time and sets the loom to be restarted so that the stop time is relatively short. On the other hand, when the loom stops once during unmanned operating hours, such as night time or holidays, the loom stops for a continuous long period of time until the succeeding normal working hours occur. Under such circumstances, it is necessary to control the warp tension so as to be an appropriate value depending on the length of the stop page of time of the loom.